Note: Compatible with any 5.56 NATO chambered AR-15, including Gas Piston Systems where the piston enters the receiver no more than 1 - 7/8 inch. Only for use in 5.56 NATO chambered AR-15 rifles.
Setup is less than 30 seconds. Ammo is 1/10 of the price of 5.56 ammo, so that means a significant savings to you.